Monday, June 26, 2006

Beth and I went on vacation to San Francisco back in April. On our first day there, we took the ferry over to Alcatraz as any good tourist would do. Alcatraz itself was awesome and I actually found my life Golden-crowned Sparrow and Brandt's Cormorant there along with a zillion Western Gulls. Aside from the birds, there were many beautiful garden areas that we explored. One of these garden areas is where we found a very strange inhabitant of Alcatraz Island. Resembling a prisoner's leftover turd, the mass of yellow goo pictured at right is actually a mollusk - the aptly named Banana Slug (Ariolimax columbianus). This yellow critter is actually the second largest slug in the world (the largest being Limax cinereoniger of Europe).

The Banana Slug is a native of moist, Pacific-coast forests where it moves along slowly with its one muscular foot. While cruising along, it eats and decomposes leaves, fungus, and animal droppings. Like all slugs, it's body is covered in a sticky slime. Interestingly, this slime has many functions. These include keeping the slug's skin moist so it can breathe through it, protecting the slug from predators who can't eat the slime, lubricating the surface for movement, and aiding with mating since females can produce a pheromone in their slime.

Another interesting thing about the slime is that scientists have tried to reproduce slug slime because it makes a great natural glue and may be of use in the medicine. For some unknown reason, scientists have not been able to succesfully reproduce it.

Despite their slimey coating, they do have some predators including raccoons, geese, garter snakes, and salamanders. Raccoons and geese have been known to roll the slugs in dirt to eliminate the slime so they can eat them.

After looking up Banana Slugs on Google, I was surprised to learn so many interesting things about them. It's surely turned me into a fan, but not as much of a fan as UC Santa Cruz!